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Cloudy skies call for more sunshine vitamin: The benefits of vitamin D

Right now, the skies are more gray than sunny. The winds are more brisk than warm. Let’s face it; it’s March in Ohio. And as we wait for the sunshine to return to The Buckeye State, we still need our vitamin D to be at our best.

What is vitamin D?

Vitamin D is a substance used by the body to maintain health. Vitamin D is essential because it helps the body absorb calcium and regulates phosphorus levels. Both calcium and phosphorus are essential for the maintenance of bone health and also have a role in supporting immune system function. Vitamin D is also necessary for the growth of your teeth. Preliminary studies have shown that adequate intake of vitamin D could help prevent certain colon, breast, and prostate cancer. Vitamin D could also have a role in warding off heart disease, diabetes, and multiple sclerosis.

Where does vitamin D come from?

Vitamin D is often called the “sunshine vitamin.” Your body produces vitamin D when you expose your skin to the sun’s ultraviolet rays. The skin’s production of vitamin D varies with season, cloud cover, latitude, and air pollution levels.

Vitamin D does occur naturally in some foods- mainly fish such as tuna, swordfish, and salmon, fish liver oils, and egg yolks. It is often added to milk and orange juice. Vitamin D supplements are also available over the counter.

How much do I need?

The Institute of Medicine recommends 600 international units (IU) of vitamin D per day for ages 1-70 and 800 IU for adults older than age 70. Higher doses are recommended for the elderly to help prevent bone loss and osteoporosis.

What causes vitamin D deficiency?

Many factors can lead to low levels of vitamin D. As we age, our skin doesn’t make vitamin D quite as well. People who have minimal exposure to sunlight (nursing home residents, people who live in northern latitudes with significant cloud cover) are at higher risk of developing vitamin D deficiency. People with dark skin are at greater risk as their skin has more melanin which reduces their ability to synthesize vitamin D from sun exposure.

Several diseases can also affect vitamin D levels. Crohn’s disease, Celiac’s disease, and cystic fibrosis can all inhibit the gut’s ability to absorb vitamin D resulting in deficiencies. Obesity and kidney disease have also been linked to lower vitamin D levels. People who undergo gastric bypass surgery are also at risk for deficiency.

How do I know if I’m low and what can I do about it?

If you spend little time outside, have any of the conditions above, or are 70 years or older, you should talk to your doctor about having your vitamin D levels checked. You can do this with a simple blood test. Vitamin D levels less than 30 ng/mL are usually considered low and require treatment, typically in the form of supplements.

Based on your levels, your age, and the presence of other medical problems, your doctor will decide the appropriate dose for you. Dosage can range from 1000 IU per day up to 50,000 IU per week for defined periods of time. You can get too much vitamin D. Vitamin D toxicity can lead to high calcium levels and cause nausea, vomiting, abdominal pain, and kidney stones. The upper limit on daily vitamin D intake as recommended by the Institute of Medicine is 4,000 IU.

It is important to talk to your doctor before starting any vitamin D supplementation.

Looking for a primary care doctor? Check out our resources.


Headshot photo of Ashley Chambers, MD, Internal MedicineAbout Dr. Ashley Chambers

Dr. Ashley Chambers is a board-certified internal medicine physician practicing in Columbus, Ohio.

Originally from Toledo, Ohio, Ashley graduated from the Ohio State University with a degree in Biology and went on to earn her medical degree at the Wright State University Boonshoft School of Medicine. She returned to buckeye country to complete her internal medicine residency at the Ohio State University Wexner Medical Center.

Ashley now practices as a full-time primary care physician. She is an advocate for wellness and believes this is best achieved through smart lifestyle choices and preventative medicine. She is passionate about the power of exercise and spends free time training for local running races and exploring the trails of Columbus with her dog, Gwen. She enjoys experiencing other cultures and countries with her husband, John. Most recently, they headed south of the equator to spend the New Year holiday in Buenos Aires, Argentina.


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